1. Field of the Invention
The present invention relates to an imaging device, such as a digital still camera, a digital video camera, and the like, and a method of image processing. More particularly, the present invention relates to an imaging device which is capable of obtaining an image focused on a target person's face and an imaging method thereof.
2. Description of the Related Art
There are many scenes where the photographic subject is one or more person(s), and it is important to photograph the person's face clearly. Under this circumstance, a camera implementing a face-recognition function is commercialized by various manufacturers.
The face-recognition function is achieved by a technology that detects a face region, by matching facial patterns, such as eye, nose, mouth or the like. The face-recognition technology is used for optimizing image quality factors of the detected face region so as to obtain an image that contains a clear face. The image quality factors can be a color reproduction of skin, an edge reinforcement, an exposure or the like.
In addition to the above-mentioned image quality factors, a focus function by which the camera can focus on the person's face is also important. But there are many scenes where the conventional auto-focus implemented camera does not focus well on the person's face. For example, there is a scene where it is difficult to focus on a person's face, as desired, because of limitations of the focal algorithm. Especially, this happens where several people to be photographed are at different distances, and a photographing condition where the focus length is on the telephoto side and the focal depth is shallow.
To overcome this problem, Auto-Focus bracket photographing is known. Auto-Focus bracket photographing obtains several images with different focal positions, and then a best focused image is selected among the several photographed images.
Currently, selecting a best focused image is only implemented in PC software. Therefore, a user is forced to confirm each image on a monitor of the PC. Since this technique is difficult and time consuming, it is desired to implement the technique on a camera. But it has limitations to select high quality image, 10 million pixel level image, on a monitor with VGA (Video Graphic Array) size of the camera.
Laid-open Japanese Patent Applications (JP2003-75717, JP2006-337080, JP2003-107335) disclose a combination of a face recognition technology and an auto-focus mechanism.
Japanese Patent Application (JP2005-277813) discloses a combination of Auto-Focus bracket photographing and an image extraction technique.
There is no known camera that is capable of face recognition technology and Auto-Focus bracket photographing and the image extracting technique.